Product Design Feature

Design problems with the other conventional materials of construction are usually solved with the aid of textbooks or handbooks that refer the reader to data sheets where the characteristics of a specific material are listed. However, products designed with plastics involve some special considerations when using these textbooks or handbooks as reviewed in Chapter 2. 

Plastic material suppliers provide material data sheets for each grade they produce. At first glance, there could be a tendency to apply the plastic information in a similar fashion to that of other materials. If such a procedure were to be followed, the result would not only lead to disappointment but also perhaps even to failure for many products. The reason for the difference in treating the plastic data sheets from those of other materials is the behavior of plastics under load and under varying environmental conditions, which normally are not factors with other materials such as steel (Chapter 2). 

The reaction of plastics under test conditions to their behaviors is explained in other Chapters, particularly Chapters 2,5 to 7. Until this phase of the information is properly understood, it is best not to apply the numbers from the data sheet, for they can be a source of misinterpreted information. A con- 

Another factor to consider in the early stages of design is material selection in relation to cost per volume rather than by weight. This subject volume vs. weight will be reviewed latter in this chapter entitled Analysis Method. Since the material value in a plastic product is usually over one-half of its overall cost, it becomes important to select a candidate material with extraordinary care. 

After a material type and grade that will fulfill performance requirements has been decided upon, steps should be taken to ensure that degrading features such as inside sharp comers, nonuniform wall thicknesses, etc., are 

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Mistake-proofing can be accomplished by product design features in order that the possibility of incorrect assembly, operation, or handling is avoided. In such cases the requirements for mistake-proofing need to form part of the design input requirements for the part. 

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